This is the first phase of research to determine fuel alternatives for Corps of Engineers medium-speed diesel engines. The literature has been searched to provide a background in current research and to identify the most promising alternatives to petroleum fuel. The criteria assessed were performance-based, with most variables compared to a No. 2 diesel fuel baseline. Results indicate that liquified coal, cetane-improved alcohol, and vegetable oils may be suitable alternatives. However, since much of the data reviewed were based on high-speed engines, additional data on medium-speed engines must be gathered making final recommendations.